1. Field of the Invention
The present invention relates to a personal identification method, a personal identification apparatus, and a computer readable recording medium that stores a program for realizing the functions of the personal identification apparatus, wherein, in personal identification using data indicating physical features, such as finger prints, of the subject, the determination of identification is carried out using as a reference the degree of similarity of these physical features.
2. Description of the Related Art
The personal certification method using a plurality of individual physical features (Japanese Unexamined Patent Application, First Publication, No. Hei 8-16788) is an example of a conventional personal identification method. This method reads a plurality of individual features such as voice, finger prints, and handwriting, partitions the read feature parameters into a plurality of categories that reflect these individual features, unifies each of the partitioned categories by applying a weight depending on the ease of the recognition of these individual features, unifies each feature parameter obtained by this unification by applying a weight depending on the ease of the recognition of these individual features, and carries out recognition of the subject by comparing these unified results with threshold values.
In addition, the fingerprint verification apparatus disclosed in Japanese Unexamined Patent Application, First Publication, No. Hei 10-124669, is a personal recognition apparatus. This fingerprint verification apparatus outputs an image signal by optically extracting a fingerprint, converts this image signal into fingerprint image data, extracts fingerprint feature quantities from this fingerprint image data, and outputs the code label of the closest code vector to one frame of this fingerprint feature quantity. Thereby, one sequence of a quantified code sequence for one sequence of fingerprint feature quantity is found, a statistical probability model is inferred using this quantified code sequence, an acceptance probability of the symbol sequence of the identified fingerprint is found by the statistical probability models of each registered finger, and if the acceptance probability exceeds a preset threshold, the person who is the object of the identification is determined to be the registered person.
Furthermore, the fingerprint sensor disclosed in Japanese Unexamined Patent Application, First Publication, No. Hei 8-138046, is a personal identification apparatus. This fingerprint sensor determines whether or not the fingerprint is that of the person based on the correlation output obtained by calculating the optical correlation between reflected light that contains the ridges of the fingerprint obtained on the reflective surface of a prism with which the part of a finger having the fingerprint is in contact, and a fingerprint image registered in advance as being that of the person. A Fourier spectrum integration value detection device that detects the integral value of the Fourier spectrum of the reflected light and a correlation output central value detection device that detects the peak value or integral value of this correlation output are provided, the ratio of the Fourier spectrum integral value of the reflected light and the peak value or integral value of this correlation output serves as the decision value, and by comparing this decision value with a predetermined threshold value, determines whether or not the person is the person to be identified.
In the conventional personal identification methods and personal identification apparatuses described above, the verification threshold value for identifying whether or not the person is the person to be identified uses a constant value. This is because the setting of the verification threshold value is difficult.
In the conventional personal identification methods and personal identification apparatuses described above, because the verification value for determining whether the person is the person to be identified or not uses a constant value, by setting the verification threshold value high, the danger of identifying the person to be identified as another person is decreased, but, for example, in the case of using the fingerprint as the data showing the physical feature of the individual, if fingerprints of sufficient quality cannot be obtained, the person to be identified will not be identified as that person, even though the person is the person to be identified.
Contrariwise, when the verification threshold value is set low, in the case that the fingerprint quality is not high, the person can be identified, but there is the problem that the next time a different person may be mistaken for that person.
In consideration of these problems, it is an object of the present invention to provide a personal identification method, a personal identification apparatus, and a recording medium that sets various separate threshold values for each of the feature data extracted from the data representing the physical features of the individual without decreasing the probability of excluding other people and improving the identification rate of the person.
A first aspect of the present invention is a personal identification method that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and wherein this individual threshold value is calculated based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution between the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding verification data.
According to the first aspect of the invention, because of this personal identification method that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and wherein this individual threshold value is calculated based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution between the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding verification data., identification of the individual is possible even in the case that the quality of the input data showing the physical characteristics of the individual who is the verification source is low and the verification score of the pre-registered feature data of the verification object is low.
A second aspect of the invention is a personal identification method that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and wherein the verification result of the feature data extracted from the data showing the physical features of the individual who is the verification source and all pre-registered feature data is found, and the verification score showing the verification results and the separate threshold value data set depending on each type of pre-registered feature data are compared in sequence, and the individual is identified based on this comparison results.
According to the second aspect of the invention, because the verification result of the feature data extracted from the data showing the physical features of the individual who is the verification source and all pre-registered feature data is found, and the verification score showing the verification results and the separate threshold value data set depending on each type of pre-registered feature data are compared in sequence, and the individual is identified based on this comparison results, inputting in advance the designated data (ID data) that specifies the individual feature data of the verification object is unnecessary.
A third aspect of the invention is a personal identification method according to the first and second aspects, wherein the separate threshold values are set at the median value of the highest score of the degree of resemblance calculated when verifying the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding data, and the lowest score in the verification score distribution which is expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source.
According to the third aspect of the invention, in the personal identification method according to the first and second aspects, because the separate threshold values are set as the median score of the highest score of the degree of resemblance calculated when verifying the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding data, and the lowest score in the verification score distribution which is expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source, by producing the separate threshold values for data showing the registered feature data depending on the quality of the input data showing the physical features of the individual who is the verification source, it is possible to carry out a determination of acceptance in the personal identification in line with the score characteristics of the feature data extracted from the data showing the physical features of the respective individuals.
A fourth aspect of the invention is a personal identification method according to the first through third aspects, wherein the separate threshold values are updated based on the verification results of the feature data extracted from the data showing the physical features of the individual who is the verification source and the pre-registered feature data.
According to the fourth aspect of the invention, in the personal identification method according to the first through third aspects, because the separate threshold values are updated based on the verification results of the feature data extracted from the data showing the physical features of the individual who is the verification source and the pre-registered feature data, it is possible to set the separate threshold values when carrying out personal identification at optimal values.
The fifth aspect of the present invention is a personal identification method that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and wherein a separate threshold value calculation device is provided that calculates the separate threshold values based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding feature data.
According to the fifth aspect of the invention, because of a personal identification method that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifying the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and wherein a separate threshold value calculation device is provided that calculates the separate threshold values based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding feature data, identification of the individual is possible even in the case that the quality of the input data showing the physical characteristics of the individual who is the verification source is low and the verification score of the pre-registered feature data of the verification object is low.
A sixth aspect of the invention has an input device that inputs designated data that specifies data showing physical features of the individual and pre-registered feature data of the verification object, a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data read from the memory device based on the verification scores showing the verification results and the designated data.
According to the sixth aspect, because of the data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data read from the memory device based on the verification score showing the verification results and the designated data, identification of the individual is possible even in the case that the quality of the input data showing the physical characteristics of the individual who is the verification source is low and the verification score of the pre-registered feature data of the verification object is low.
A seventh aspect of the invention has an input device that inputs data that specifies data showing physical features of the individual and a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device in sequence all read pre-registered feature data of the verification object, verifies the feature data of the verification source and the pre-registered feature data of the verification object, totals the comparison results of the verification score showing the verification results and the separate threshold data corresponding to the pre-registered feature data read from the memory device, and carries out the identification of the individual based on summation results.
According to the seventh aspect, because of the data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device in sequence all pre-registered feature data of the verification object, verifies the feature data of the verification source and the read pre-registered feature data of the verification object, totals the comparison results of the verification score showing the verification results and the separate threshold data corresponding to the pre-registered feature data read from the memory device, and carries out the identification of the individual based on the summation results, inputting in advance the designated data (ID data) that specifies the individual feature data of the verification object is unnecessary.
An eighth aspect of the invention is a personal identification apparatus according to the sixth aspect wherein the data processing device verifies the feature data of the verification source and the read pre-registered feature data of the verification object, and updates the separate threshold value data based on the comparison results of separate threshold data read from the memory device based on the verification score showing the verification results and the designated data.
According to the eighth aspect of the invention, because of the personal identification apparatus according to the sixth aspect wherein the data processing device verifies the feature data of the verification source and the read pre-registered feature data of the verification object, and updates the separate threshold value data based on the comparison results of separate threshold data read from the memory device based on the verification score showing the verification results and the designated data, it is possible to set the separate threshold values when carrying out personal identification at optical values.
A ninth aspect of the invention is a personal identification apparatus according to any of the fifth through eighth aspects, wherein the separate threshold values are set at the median value of the highest score of the degree of resemblance calculated when verifying the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding data, and the lowest score in the verification score distribution which is expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source.
According to the ninth aspect of the invention, because the separate threshold values are set as the median score of the highest score of the degree of resemblance calculated when verifying the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding data, and the lowest score in the verification score distribution which is expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source, by producing the separate threshold values for the registered feature data depending on the quality of the input data showing the physical features of the individual who is the verification source, it is possible to carry out a determination of acceptance in the personal identification in line with the score characteristics of the feature data extracted from the data showing the physical features of the respective individuals.
A tenth aspect of the invention is a computer readable recording medium that stores a program that can realize the functions of a personal identification apparatus that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and a computer readable medium records a program for realizing the features of the personal identification apparatus having a separate threshold value calculation device that calculates this separate threshold value based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution between the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding verification data.
According to the tenth aspect of the invention, because of a personal identification apparatus that finds the verification result of feature data extracted from input data showing the physical features of the individual who is the verification source and pre-registered feature data of the verification object, and identifies the individual by whether or not the degree of similarity obtained by the verification results exceeds a separate threshold value set to correspond to pre-registered feature data, and a computer readable medium records a program for realizing the features of the personal identification apparatus having a separate threshold value calculation device that calculates this separate threshold value based on the verification score distribution of the feature data extracted from the data showing the physical features of the individual who is the verification source and the corresponding feature data, and the verification score distribution between the feature data extracted from the data showing the physical features of the individual who is the verification source and the non-corresponding verification data., by reading into a computer system a program recorded on this recording medium and executing it, identification of the individual is possible even in the case that the quality of the input data showing the physical characteristics of the individual who is the verification source is low and the verification score of the pre-registered feature data of the verification object is low.
An eleventh aspect of the invention is a computer readable recording medium that stores a program for realizing the functions of a personal identification apparatus having an input device that inputs designated data that specifies data showing physical features of the individual and pre-registered feature data of the verification object, a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data read from the memory device based on the verification score showing the verification results ant the designated data.
According to the eleventh aspect of the invention, because of a computer readable recording medium that stores a program for realizing the functions of a personal identification apparatus having an input device that inputs designated data that specifies data showing physical features of the individual and pre-registered feature data of the verification object, a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data read from the memory device based on the verification score showing the verification results and the designated data, by reading into a computer system a program recorded on this recording medium and executing it, identification of the individual is possible even in the case that the quality of the input data showing the physical characteristics of the individual who is the verification source is low and the verification score of the pre-registered feature data of the verification object is low.
A twelfth aspect of the invention is a computer readable recording medium that stores a program for realizing the functions of a personal identification apparatus having an input device that inputs designated data that specifies data showing physical features of the individual and pre-registered feature data of the verification object, a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the pre-registered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data.
According to the twelfth aspect of the invention, because of recording on a computer readable medium a program for realizing the functions of a personal identification apparatus having an input device that inputs designated data that specifies data showing physical features of the individual and pre-registered feature data of the verification object, a memory device that stores the feature data sets that are extracted from the data showing the physical features of the individual and the separate threshold value data sets that are set according to the respective character data sets, and a data processing device that extracts a plurality of feature data from the data showing the physical features of a plurality of individuals input by the input device during registration, determines the feature data that is to be registered based on the verification results between the plurality of feature data, calculates the separate threshold values by verifying the feature data to be registered and the preregistered feature data and carrying out statistical processing on the verification data, stores in the memory device the feature data to be registered and the separate threshold value data, and at the same time extracts feature data of the verification source from the data showing the physical features of the individual input from the input device during verification, reads from the memory device the pre-registered feature data of the verification object based on the designated data, verifying the feature data of the verification source and the pre-registered feature data of the verification object, and carries out the identification of the individual based on the comparison results of the separate threshold data, by reading into a computer system a program recorded on this recording medium and executing it, inputting in advance the designated data (ID data) that specifies the individual feature data of the verification object is unnecessary.
A thirteenth aspect of the invention is a personal identification apparatus according to the sixth aspect having a computer readable recording medium storing a program for realizing the functions of the personal identification apparatus, wherein the data processing device verifies the feature data of the verification source and the pre-registered feature data of the verification object, and updates the separate threshold value data based on the results of a comparison of the verification score showing the verification results and the separate threshold value data read from the memory device based on the designated data.
According to the thirteenth aspect of the invention, because of the personal identification apparatus according to the sixth aspect having a computer readable recording medium storing a program for realizing the functions of the personal identification apparatus, wherein the data processing device verifies the feature data of the verification source and the pre-registered feature data of the verification object, and updates the separate threshold value data based on the results of a comparison of the verification score showing the verification results and the separate threshold value data read from the memory device based on the designated data, by reading the program stored on the recording medium into a computer system and executing it, it is possible to set the separate threshold values to optimal values when carrying out personal identification.
The fourteenth aspect of the invention according to the fifth through eighth aspects is a computer readable recording medium that stores a program for realizing the functions of a personal identification apparatus wherein the separate threshold values are set to the median value of the highest score of the degree of similarity extracted when verifying the feature data extracted from data showing physical features of the individual who is the verification source and the non-corresponding feature data, and the lowest score in the verification score distribution expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source.
According to the fourteenth aspect, because of a computer readable recording medium that stores a program for realizing the functions of a personal identification apparatus wherein the separate threshold values are set to the median value of the highest score of the degree of similarity extracted when verifying the feature data extracted from data showing physical features of the individual who is the verification source and the non-corresponding feature data, and the lowest score in the verification score distribution expected to be obtainable for the feature data extracted from the data showing the physical features of the individual who is the verification source, by reading the program stored on the recording medium into a computer system and executing it, it is possible to carry out a determination of acceptance in the personal identification in line with the score characteristics of the feature data extracted from the data showing the physical features of the respective individuals by producing separate threshold values for pre-registered feature data according to the quality of the data showing the physical features of the individual who is the verification source.